A continuing frustration for population researchers interested in the developing countries of Asia and else- where, is the lack of demographic and social data compiled at the level of cities, towns and villages. In- dia's census authorities have recently tabulated a large set of census-collected variables at the individual settlement level?these are termed population census abstracts?for places ranging in size from small ru- ral villages to towns and upward to the largest of India's municipalities. For cities and towns, the tabula- tions include information on within-city units (wards and the like), which is most unusual. The electronic versions of these data have been made available for download on the public-domain census website http: //www.censusindia.gov.in/2011census maintained by the Indian government since 2014. Responding to PAR-16-149, Archiving and Documenting Child Health and Human Development Data Sets, we propose to create an integrated database of the settlement-level census records for the censuses of 1991, 2001, and 2011, and to place that collection into a public-domain archive along with documentation and com- puter programs showing users how to access and analyze the data. The combined data will enable researchers to better understand the recent complex history of urbanization in India, and to estimate the exposure of rural and urban-dwellers to a range of environmental risks at an unprecedented level of spatial and social detail. Previous research conducted under National Science Foundation award 1416860, has supported the down- loading of many thousands of data-?les and documentation for the three censuses, and has enabled Principal Investigator Mark Montgomery (Population Council, New York) to produce complete collections of primary cen- sus abstracts for the censuses of 2011 and (in process) 2001. The linkage of individual settlements across these two censuses is underway. The present application will draw additionally on the expertise and local knowledge of Co-Investigator Bidhubhusan Mahapatra and Ms. Monika Walia in the New Delhi of?ce of the Population Council, to resolve and document problems arising from missing settlement data and data inconsistencies. The research team will then complete the integration of the 1991 census into the database. The products of this research?the integrated census data, a linkage ?le enabling individual settlements to be tracked across the 1991 to 2011 censuses, and a full set of R programs to provide guidance to users of these data?will be submitted to the ICPSR archives under the Data Sharing for Demographic Research Program. To spread awareness and encourage informed use of the integrated package, a Population Council web-site will be established to collect user-identi?ed errors and to gather other feedback, a journal article announcing the new data will be submitted, and a seminar will be organized at the Census Data Centre of Jawaharlal Nehru University (supported by the Of?ce of the Registrar General and Census Operations in India) to present the database and encourage census experts to scrutinize the data and identify areas for further improvement.